Our Port Flow Analyzer for flow bench testing has several features for making several measurements of cylinder head performance. For head flow, pretty much anything that improves CFM flow improves the HP potential of the head. But after measuring CFM, there are several other measurements which can give better insight into one particular head runs well on the dyno or the track, and another head with equal or sometimes even less flow can run much stronger. These are the hard earned “black arts” of head porting which many engine builders are reluctant to share. Questions these engine builders are looking to answer include: Read the rest of this entry »

There is nothing magic about 28″ water. Famed engine builder Smokey Yunick picked this pressure (about 1 psi) many years ago (probably in the 1960s) as what he thought was reasonable, and it stuck. It is now the industry standard.Read the rest of this entry »

An engine dynamometer is used to measure the engine’s power. Dyno tests can be done different ways, but the most common method in the racing world is a sweep test. A sweep test is where you slowly (or quickly) accelerate (or decelerate) through the RPM range with the engine at full power. This must be done somewhat smoothly and slowly, taking about 5 to 10 seconds for good accuracy.

Recently a well known racing head porter asked for some graphics (pictures) for an article on head port design. His article dealt with there is more to a head’s performance potential than just CFM flow numbers.

When building or modifying an engine for all-out racing, street/strip performance, trailer towing, or most any application, there are many variables to consider. One critical variable is the Compression Ratio or CR. Compression ratio is the amount of “squeeze” the piston puts on the air fuel ratio before it lights the fire. And, more importantly, it is the amount of expansion or “push” these hot, high pressure, combusted gases put on the piston. The more amount of expansion, the more amount of heat and pressure energy can be extracted from each combustion event. Read the rest of this entry »

Our engine performance simulation program (Engine Analyzer Pro) produces what we call RPM Data like torque, HP, fuel flow, BSFC, etc at each RPM of the run. It also produces Cycle Data which are things like cylinder temperature, cylinder pressure, piston thrust on the wall, intake valve lift, intake valve flow, etc at every 4 degrees of crankshaft rotation. (Behind the scenes the data is being calculated at something more like every .1 degrees, but we only report it at every 4 degrees.) Read the rest of this entry »